UNDERCUT EMBOSSING PLATES AND EMBOSSING METHOD

DESCRIPTION

The present invention relates to a new type of plates for performing a particular processing of materials made of leather or the like, in particular for performing an undercut embossing.

Background

Embossing is a particular surface processing of a material with which several types of patterns and wefts are printed on a sheet material, with the purpose of modifying the external aspect thereof and/or improving the structural features thereof, in terms of keeping the shape imposed in the production/industrial processing phase.

Embossing is used in the productive processes of several processes, for example used in the processing of paper products such as for example napkins, absorbent paper, etc., or in the processing of metal plates to provide a non-slip or structurally stiffer surface shape or still in the processing of natural leather and fake leather.

Several embossing techniques are known nowadays. All of them share in common the general principle of deforming the material to be processed.

The deformation takes place by pressure, for example by making the sheet material to pass between two rollers parallel therebetween, in case suitably spaced apart and bearing on their surface (on at least one of the two) an incision in negative with respect to the wished final shape.

Wholly analogous principle is applied in case of press processing. The sheet material in this case is placed inside a mould constituted by two parallel plates, the contact surface thereof is processed as shown above, and which indeed are pressed one against the other one with the material to be processed therebetween. In case of processing the natural skin and the fake leather, embossing is typically used to print patterns, to engrave motifs or wefts, with the purpose of obtaining particular aesthetical finishing.

Sometimes it is used even to ennoble second-choice natural leathers.

In particular in the field of the fake leather, typical processing for embossing is the one implemented for example with the purpose of providing to said fake leathers an aspect as similar as possible to the natural leather (for example by reproducing the crocodile scales or the rugosity of a cow leather, etc.).

Aesthetical effects particularly similar to the natural skin are provided nowadays by using machines performing undercut embossing.

It is a special processing performed by means of particular machines, called carving machines, performing tilted incisions on the fake leather, by means of thin sheets sliding along the cutting planes whereon the leathers to be incised are positioned.

This processing succeeds in providing a final effect on the carved leather which is particularly effective in making it similar to the natural leather.

However, this processing is also used both on fake leather and on natural leather, with the only purpose of obtaining relief shapes and particular finishing which would not be otherwise possible to be obtained by using the normal machines used for embossing, that is the rollers and the plates for embossing.

However, the apparatuses used to date (carving machines or other) for the undercut embossing allow to perform such processing with not optimum precisions, above all with reference to the specific field of the processing of the fake leather for implementing natural-like patterns. Moreover, said machines, due to the fact that they have to implement hundreds of cutting cycles and passages along the leather, suffer from enormous productivity limits, due to their slowness, thus involving high production costs affecting the cost of the finished material.

Therefore, the technical problem of implementing a system capable of performing undercut embossing in precise, simple, quick way and with low cost remains unsolved. Technical problem solved by the invention

The object of the present invention is to provide a solution allowing to implement processing of undercut embossing in a simple, quick way and with reduced costs.

An additional object of the present invention is to obtain a technical solution which could be easily adapted to the machines already used for the embossing processing.

Still an additional object of the present invention is to obtain, thanks to the new technical solution, a semi-finished product (natural leather, fake leather, other...) provided with aesthetical features and finishing having qualities comparable or higher than the one obtainable with the conventional processing using carving machines.

A particular specific additional object of the present invention, at last, is to obtain a semi-finished product of fake leather the final aspect thereof is similar as much as possible to that of a natural leather.

These and additional objects as it will be clear hereinafter have been obtained by means of a plate for undercut embossing as defined in the independent claim Nr. 1.

The present invention further relates to an embossing counterplate as defined in the independent claim Nr. 8.

The present invention further relates to a kit for undercut embossing as defined in the independent claim Nr. 12.

Still, the present invention further relates to a process for undercut embossing as defined in the independent claim Nr. 13.

Additional features of the present invention are defined in the corresponding depending claims.

The present invention involves several and evident advantages with respect to the known art.

The advantages, together with the features and use modes of the present invention will result evident from the following detailed description of preferred embodiments thereof, shown by way of example and not for limitative purpose. Brief description of the figures

Hereinafter in this description the drawings shown in the enclosed figures will be referred to, wherein:

• figure 1 schematizes the typical embossing apparatus of known art;

• figure 2 schematizes an apparatus of undercut embossing according to the present invention;

• figure 3 shows an example of undercut embossing plate according to the present invention;

• figure 4 is a view schematised in side section of an undercut embossing plate according to the present invention;

• figure 5 shows schematically a flat press wherein an undercut embossing plate and an embossing counterplate according to the present invention are used; and

• figure 6 is an enlarged detail of figure 5.

Detailed description of preferred embodiments

The present invention will be described hereinafter by making reference to the above-mentioned figures.

In particular, by firstly making reference to figure 1 , this shows schematically a typical embossing apparatus 1 according to the known art.

The apparatus 1 comprises two opposite plates 2, 3, therebetween the sheet material to be processed 10 is placed.

At least one of the plates 2, 3 has the processed contrast surface, so that by tightening therebetween the two plates with an adequate pressure, the material deforms by keeping, at the end of the process, such surface deformation which is naturally complementary to the one existing on the contrast surface of the plate(s).

The two plates 2, 3 are implemented and assembled so that the respective contrast surfaces are exactly parallel therebetween and the force to produce the required pressure is exerted in orthogonal direction with respect to the contrast surfaces.

By making now reference to figure 2, this shows schematically a possible apparatus of undercut embossing according to the present invention.

The present invention is based upon the fact of having experienced that a different distribution and orientation of the forces during pressing produces an ameliorative effect in the final aspect of the processed sheet material which appears clearly more realistic than the standards of known art.

According to the present invention, it is possible to obtain the described advantageous effect of an undercut embossing by modifying suitably the traditional embossing plates and/or embossing counterplates.

In this sense, according to the present invention, an undercut embossing plate is implemented so as to have, during use, the respective contrast surface not exactly orthogonal to the direction of the applied force Fp.

This shape is schematized by way of example in figure 2.

In this figure an apparatus 11 is schematized providing a plate 20 and a counterplate 30 shown in cross section, under use operating conditions, and with a sheet material to be processed 10 interposed therebetween.

The plate 20 and the counterplate 30, during use, have respective contrast or coupling surfaces, respectively designated with 23 and 33, substantially parallel therebetween, but tilted by a contrast angle a comprised between 0.5° and 7° with respect to a direction D orthogonal to the pressing force Fp.

According to some possible embodiments of the present invention, the contrast angle a is comprised between 1 ° and 4°.

Preferably, the contrast angle a is comprised between 2° and 3°.

In a preferred embodiment of the invention said undercut embossing plate 20 is made of aluminium. Figure 3 shows, by pure way of example, an undercut embossing plate 20 according to the present invention wherein a scale-like processing is visible which, as already explained, can assume different shapes depending upon the wished end result.

In particular the plate processing can be like scales of various type or can be constituted by any type of geometry and pattern of interest.

In particular, the undercut embossing plate 20 comprises a first face 21 thereon a contrast surface 23 is defined which, in turn, has a plurality of regions 24 shaped according to the pattern of interest, for example shaped like scales

By making also reference to figure 4, the undercut embossing plate 20 comprises a second face 22 opposite to the first face 21.

According to the present invention, the contrast surface 23 can be generally approximated by a plane P, tilted by the above-mentioned contrast angle a comprised between 0.5° and 7° with respect to the direction D, orthogonal to the pressing force Fp, and substantially coincident with the direction of the second face 22 of the plate 20.

According to some possible embodiments of the present invention, the contrast angle a is comprised between 1 ° and 4°.

Preferably, the contrast angle a is comprised between 2° and 3°.

According to an embodiment of the present invention, the scale-like shaped regions 24 are generally flat and tilted by a printing angle b comprised between 5° and 40° with respect to the direction D as already defined.

According to some possible embodiments of the present invention, the printing angle b can be comprised between 10° and 35°.

Preferably, the printing angle b can be comprised between 25° and 30°.

Moreover, by still making reference to figure 4, preferably, each scale-like shaped region 24 forms a tooth 35 comprising a leading surface 36.

Such leading surface 36 is preferably tilted by a leading angle g with respect to the direction D of the second face 22 of the plate 20. According to some possible embodiments of the present invention, the leading angle g can be comprised between 45° and 90°.

According to some possible embodiments of the present invention, the leading angle g can be comprised between 55° and 80°.

Preferably the leading angle g is comprised between 65° and 70°.

The subsequent figures 5 and 6 illustrate schematically a flat press 50 on the upper plane thereof 51 an undercut embossing plate 20 according to the present invention is assembled, and on the lower plane thereof 52, instead, an embossing counterplate 30 is assembled.

The sheet material to be processed 10 is placed between the plate 20 and the counterplate 30. According to the present invention, said embossing counterplate 30 is used as opposed to an undercut embossing plate 20 as described sofar.

As shown in figure 5, the counterplate 30 comprises a first face 31 having a coupling surface 33 generally flat and tilted by a coupling angle o.

According to the present invention, the coupling angle o can be comprised between 0.5° and 7° with respect to the already defined direction D.

According to some possible embodiments of the present invention, the coupling angle o is comprised between 1° and 4°.

Preferably, the coupling angle o is comprised between 2° and 3°.

It is to be meant that, by using a plate/counterplate pair, these should be selected so that the coupling angle o has a size equal to the already previously defined contrast angle a.

The embossing counterplate 30, according to preferred embodiments, can have a substantially smooth or embossed coupling surface 33.

The embossing counterplate 30, according to preferred embodiments, can be made of aluminium, teflon, or other material suitable to the purpose, able to resist to the pressures and operating temperatures and to favour elastically the incision procedure performed by the undercut embossing plate 20.

Preferably said material is teflon. In particular the use of teflon instead of the aluminium classically used for manufacturing plates, would favour a longer duration of the undercut embossing plate 20 and a better transfer of the pattern on the material to be processed.

At last, according to the present invention, an embossing kit can be provided comprising at least an undercut embossing plate 20 and at least an embossing counterplate 30 according to what described sofar.

At last, of course, it is to be meant that the present invention further relates to an embossing process, characterized in that it uses a flat press equipped with an undercut embossing plate/counterplate pair according to what described sofar. Said process is particularly advantageous since it allows to extend the applications for using the traditional flat presses used for standard embossing processing to special processing of undercut embossing, which up to now could be used only with particular machines, the carving machines, only dedicated thereto.

The invention then allows to implement within the industrial sector of the owners of such flat presses a certain economical advantage, on one side thanks to the greater use of the machines (and then to the reduction in the industrial cost affecting each single processed piece) and on the other side to the objective possibility of expanding their own portfolio of products which can be manufactured with said processing.

The present invention has been sofar described with reference to preferred embodiments thereof. It is to be meant that each one of the technical solutions implemented in the preferred embodiments, herein described by way of example, can advantageously be combined with the other ones, differently from what described, to create additional embodiments belonging to the same inventive core and however all belonging to the protective scope of the here below reported claims.